60 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1936 
Infested remnants of previous tomato crops along the edges of the field when 
a urn crop la being planted In adjacent or oearbj land. 
Limited biological studies on the tomato fruitworm {Heliothis obsoleta 
have disclosed thai most of the eggs of this pesl of tomato fruits are 
on the apper and lower surfaces of the tomato leaves, toward the outside • 
of tiif plant, ii seems possible that advantage may be taken of this feature and 
that :i more satisfactory control of the tomato frnitworm may be obtained 
through the use of insecticides. 
MISCELLANEOUS VEGETABLE INSECTS 
Extensive experimental work In Mississippi has demonstrated that fumiga- 
tion of seed sweetpotatoes with paradichlorobenzene, particularly in storage 
banks, is an effective method of ridding such seed of the sweetpotato weevil and 
does not Injure the viability of the seed. 
Laboratory toxicity tests conducted for the control of the vegetable w< 
in Mississippi failed to disclose any nonarsenical insecticides of sufficient tox- 
icity to this pesl to warrant further experimentation. 
in California the cleaning up of nightshade, the winter host plant of the 
pepper weevil, under the supervision of the state an«l county authorities, has 
proved of great value in reducing damage by this pest To lie effective, how- 
ever, the clean-up must he thorough and extend over a wide area. 
in preliminary steps having f<>r their objective the control of mole crickets, 
biological studies of these posts have been stressed in Florida. Much information 
has been accumulated respecting their habits, with special reference to such fea- 
tures ns may have a bearing upon control. A survey has been conducted in the 
Gulf <'o;ist and Atlantic Coastal Plain regions to determine more definitely the 
distribution and abundance of each of the principal specie- of mole crickets, with 
the result that Scapteri8CU8 acli f U8 R. and IT. was found to be the predominant 
species. 
Tests with insecticides directed against the turnip aphid in Louisiana have 
shown that insecticides containing rotenone, with sulphur and talc as diluents. 
ha\e in general been more effective in producing a satisfactory market product 
than Insecticides containing nicotine. 
Studies on the control of the principal Species Of worms affCrting lettuce in 
Arizona demonstrated that under conditions existing in that section during the 
fall of 1835, dust mixtures containing cryolite, applied 3 days after the plant- 
were thinned, gave good control of lettuce Loopers {Autographa spp.), but none 
of the Insecticides tested was effective against the beet armyworm, another 
common pest Infesting lettuce In the Southwest. 
During the course of investigations on the European earwig in the State of 
Washington, parasites of this pest Imported from Europe were liberated In 17 
localities under widely divergent environmental conditions. The parasites were 
recovered from eight of these localities and have indicated their ability To 
become established and possibly to I f some value in the control of the earwigs. 
Attempts have also been made to establish the parasite at Newport. K. I., where 
the European earwig has been a pest for many year-. In tests with various hai! 
Ingredients it was shown that flsh oil was superior to water, and that 'he 
broadcast method of bait application was more efficient than the spot method 
of applying bait to restricted areas where the earwig was known to be abundant. 
\toi I < BR SETS in PUI BTO kii o 
Studies on mole Crickets in Puerto Rico indicated that these insects j,i- ( . very 
Important economic pests on the Island. Investigations in the field demon- 
strated Hint vegetable crops suffered the greatesl degree of damage by mole 
crickets, principally because such crops are grown in Bandy soils that provide- 
:i favorable environment for these Insects. The efficiency of several mechani- 
cal, cultural, and chemical controls was Investigated, and it was found that the 
most effective method of combating these pests consists ,.r the application of a 
bait containing parts green and flour. This bail i< being extensively employed 
by tic- growers of vegetables and tobacco on the Island. Small scale field 
tests Indicated that white arsenic or sodium fluoride were superior to parts 
green as an Ingredient of the bait. Moist pile-, of sand placed in lnf< 
field- during the drj season attracted large numbers of mole crickets and Indl 
nihility of Utilizing this feature a- an aid to control. 
